Compressor unloader mechanism



July 1927- o. R. CUNDY 1 COMPBES SOR UNLOADER MBCHANI SM Filed March 31, 1924 Patented July 5, 192? Ul'l'ED OSCAR R. CU'NDY, OF DORMONT, PENNSlYLVANIl-l, ASST T0 SULLIVAN L'IACHINERY COMPANY, A CORPORATION MASSMCHUSETTS.

COMPRESSOR nnnoannn MEOETANISM.

Application filed March 31, 1324. Serial No. 703,105.

This invention relates to compressor unloader mechanisms.

It has for its object to provide an improved unloading mechanism. "A further object is to provide an improved automatic unloading mechanism. Another object i's to provide an improved unloading mechanism adapted to simultaneously and automat-icall unload a plurality of compressors. It is also an object of my invention to provide improved means whereby separate com; pressors may be automatically unloaded in steps or by my improved arrangement the same may be unloaded simultaneously without affecting the adjustment of the automatic apparatus. I

In the accompanying drawings I have shown for purposes of illustration one form which my invention may assume in practice.

(The figure is a plan view of my improved unloading mechanism.

In the illustrative form of my. invention I have shown two compressor units 1 and 2 driven by any suitable means. herein shown as an electric motor 3 disposed between the compressors. Leading from each compressor are usual discharge pipes 4 and 5 connected to a common pipe 6 discharging into a receiver 7. Mounted upon the compressors are identicalunloading mechanisms 8 and 9 for closing the intake valves or suitably controlling other valve mechanisms as desired and which are actuated. by fluid pressure from the receiver 7 In the operation of a plurality of compressors it is sometimes desirable to unload the same in steps which have re atively small limits of pressure variation between the loading and unloading; of. any one 'compressor. such condition exists and the air consump tion is relatively low, the compressor which is adjusted so as to load and unload accord ing to the intermediate pressure limits will be alternately loaded and unloaded quite frequently, whereas, if the automatic unloading means are so adjusted that there would be a wide range in the pressure limits the frequency of loading and unloading would be materially reduced and would not only save wear and tear on the unloading mechanism, but also reduce the power consumption due to the fact that it takes more than a normal amount of energy during loading of the compressor than it does dur- 'pressor 2 will be unloaded It will thus be obviousjthat when ing normal operation. H nce, the fewer nected by a common pipe 12 to the receiver 7 while separate pipes A3 and 14 conn-ect into a common cross pipe 15 in turn connected to pipes 16 and 17 leading to the unloading mechanisms 8 and 9. Disposed in the pipes 13 and 14' are usual manual control valves and 19 while disposed in the pipc 15' and between the pipes 13 and 14 is a third manual control valve 20.

In the operation of my device it will be assumed that the'pilot valve 10 is set to unload say at 9? pounds receiver pressure and to reload when the pressure drops to 95 pounds'while the pilot valve 11 is set to unloadat 100 pourirs and to reload t 90'pounds. Thus, when it is desired to unload in steps, valves 18 and 19 will be opened and valve 20 closed so that as the pressure builds up in the receiver first the compressor 1 will be unloaded when the pressure reaches 97 pounds and then the com when the pressure reaches 100 pounds and as the pressure in the receiver '7 drops, the compressor 1 'wlll first be reloaded when the pressure drops to 95 pounds and then. the compressor 2 will be reloaded when the pressure drops to 90 pounce; With th s arrangement, when the consumption islonu it will be seen that the con'iprcssor 1' would be quite frequently loaded and unloadea n great number of free, ent operations. whend to avoid such a the consumption is low I propose to close the valve 18 and open the valve 20 and let the single pilot valve ll. control both con'iprcssors. thus obtaining a. pressure variation of say 10 pounds. The result is that the compressors will be inoperative a greater length of time than before.

While l have in this application specifically described one form which my invention may assune in practice, will be understood that this form of the same is shown for purposes of illustration and that the invention may be modified and embodied in various other forms without departing from its spirit or the scope of the appended claims.

What I claim as new and desire to secure by Letters Patent is:

1. In combination, in a compressor system, a plurality of independent compressors, a plurality of pilot valves set for different unloading pressures, and means whereby said several valves may separately unload said several compressors at said different unloading pressures or one of said valves may effect unloading of all of said compressors at its specific unloading pressure.

2. In combination, in a compressor system, a plurality of independent compressors, a plurality of pilot valves set for different loading pressures, and means whereby said several valves may separately load said several compressors at said different loading pressures or one of said valves may effect loading of said several compressors at its specific loading pressure.

3. In combination, in a compressor system, a plurality of independent compressors, a plurality of pilot valves, the loading and unloading pressures being different in the case of each of said pilot valves from the loading and unloading pressures of the rest, and means whereby said several valves may separately effect the loading and unloading functions of said several compressors or one of said valves may effect the loading and unloading of said several compressors at its specific loading and unloading pressures.

I. An unloading system for a plurality of compressors comprising unloading mechanism for each of said compressors, a plurality of pilot valves therefor, one of which has loading and unloading limits on the outside of the other, and means whereby said valves may unload said compressors in steps or only one of the same may control all of said unloading mechanisms.

5. An unloading system for a plurality of compressors comprisingunloading mechanism for each of said compressors, a plurality of pilot valves therefor each having different pressure range, and means whereby said valves may unload said compressors in steps or only the one having the greatest pressure range may control all of said un-' loading mechanisms when the air consumption from said compressors is low.

6. A plurality of separate compressors driven from a common source of power, unloading means therefor, a receiver to which each of said compressors may discharge independently of the remainder, a single pilot valve actuated by fluid from said receiver, and means whereby said valve n'lay, selectively, control said several compressors si multaneously or may control'but one of said compressors.

7. A plurality of separate compressors driven from a common source of power, unloading means therefor, a receiver, a'"plurality of pilot valves, and means for simultaneously or only individually connecting the same for operation for controlling all of said compressors to effect loadingand unloading thereof in accordance with receiver pressure variations.

8. Acontrolling system for a pluralityof compressors each having an unloading mechanism, a receiver, pilot valves for each of said unloading mechanisms and having communication with said receiver, apipeleading from each of said valves, a common pipe communicating with each of said latter pipes and said unloading mechanisms, manually operable valves disposed in said pipes'between said valves and common pipe, and another manually operable valve disposed in said common pipe between said pipes leading from the pilot valves to said common pipe.

9. A controlling system for a plurality of compressors each having an unloading mechanism, a receiver, pilot valves for each of said unloading mechanisms having communication with said receiver, a pipe leading from each of said valves, a common pipecommunicating with each of said latter pipes and unloading mechanisms, shut off valves disposed in said pipes between said valves and common pipe, and another shut off valve disposed in said common pipe between said pipes leading from the pilot valves to said common pipe.

In testimony whereof I aflix my signature.

OSCAR R. CUNDY'. 

